Automatic stoker



M y 19, 1936. J. P. NORTON 2,041,204

AUTOMATIC STOKER Filed Aug. 10, 1953 6 Sheets-Sheet l ,INVENTOR dIqMEsF. NORTON A-'TTORNEY a y 9, J. P. NORTON v 2,041,204

" NW" I n, i If N (I I" I m I m El I ll llillllluu N llhll""""" IN VVVVOR JAMES B NORTON ATTORNEY May 19, 1936. J p, NORTON 2,041,204

AUTOMAT I G STOKER Filed Aug. 10, 1953 6 Sheets-Sheet 4 YINVENTOR JAMESP NORTON BY M 1.

- ATTORNEY 1 J: P. NORTON 4 AUTOMATIC STOKER I May 19, 1936. I

- Filed Aug 10, 1933 s SheetsSheet 5 II I] NORTON 'INVENTOR Fly. 6JAyE-S' I? 1. 4 s

ATTORNEY May19,193 6. J. P. NCRTON 2,041,204

AUTOMAT I C STOKER Filed Aug. 10, 1953 6 Sheets-Sheet 6 'INVENTOR JAMESP A/oRToN ATTORNEY V Patented May 19, 1936 UNlTED STATES PATENT OFFICEAUTOMATIC STOKER Application August 10, 1933, Serial No. 684,543

15 Claims.

This invention relates to automatic stokers, and more particularly tostokers of the type having a reciprocable ram to feed fuel into afurnace and a rotatablefan wheel to deliver air to the furnace forcombustion of the fuel.

The ram in such a stoker must move rather slowly, and preferably atsomewhat infrequent intervals, whereas the fan wheel must rotate at highspeedv in order to supply air in sufficient quantities and at the neededpressure. Furthermore, it is desirable that both the ram and the fanwheel be driven from a single motor, since this reduces the initial costof the construction as well as the space required. In addition, itshould be possible to vary the frequency of ram reciprocations andthereby control the rate of fuel feed. Considerable difficulty has beenencountered in devising an automatic stoker which will include theseimportant features without being complicated and expensive tomanufacture. Moreover, many of these stokers have been so bulky as toobstruct the firing aisle and interfere with the opening of the furnacedoors and the removal of ashes from the furnace.

It is accordingly one object of the invention to provide an automaticstoker which will be compactly constructed and which will obstruct thefiring aisle to a less extent than prior mechanisms for the samepurpose.

It is a further object of the invention to provide an automaticstokerincludlng a rotatable fan wheel and a reciprocable ram, togetherwith a single motor to actuate both of said parts, the entireconstruction being simple, inexpensive and compact.

It is a further object of the invention to pro-.- vide an automaticstoker including a ram reciprocable below a fuel hopper, and anelectricmotor. a fan and driving mechanism all compactly ar-- ranged in front ofthe hopper.

With these and other objects in view, as will be apparent to thoseskilled inthe art, the invention resides in the combination of parts setforth in the specification and covered by the claims appended hereto.

In accordance with the preferred embodiment of my invention, I provide aram which is reciphousing. Both the shaft and the fan wheel arev drivenby a single motor, which is preferably an electric motor located closeto and in front of the hopper. In the preferred construction, therotatable shaft is made. hollow to form a quill, and the fan wheel isdriven by means of a shaft extending axially through the quill. Thequill is provided with an eccentric which serves to reciprocate the ramthrough the medium of a connecting rod. The fan shaft is driven at acomparatively high speed, preferably by means of a chain and sprocketdrive from the motor, and the quill isdriven at a comparatively lowspeed, preferably by means of a gear train and a speed reducing chainand sprocket drive connecting the motor shaft with the gear train. Anautomatically actuated clutch is preferably utilized to start and stopthe quill at intervals and thus control the frequency of ramreciprocations.

Referring to the drawings illustrating one embodiment of the invention,and in which like reference numerals indicate like parts,

Fig. 1 is a front elevation of an automatic stoker;

Fig. 2-is a side elevation of the stoker, the fan housing beingpartially broken away to show the internal construction thereof;

Fig. 3 is a section on the line 33 of Fig. 1;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is an enlarged plan view of the clutch actuating mechanism withthe cover plate removed, certain parts being broken away for clearnessof illustration;

Fig. 6 is a section on the line 66 of Fig.5;

Fig. '7 is a section on the line 1-1 of Fig. 5;

Fig. 8 is a section on the line B8 of Fig. 5; and

Fig. 9 is a section on the line 9--9 of Fig. 6.

The embodiment illustrated comprises a fuel hopper l mounted adjacent tothe front wall ll of a furnace. Beneath the hopper is a horizontal ramcasing l2 which communicates through an opening [4 (Fig. 3) in the wallwith an underfeed retort l of well-known construction. A ram I6 isarranged to reciprocate in the ram casing l2 and thereby deliver fuelfrom the hopper l0 through the opening 14 into the retort l5.

In order to deliver air for combustion of the will be delivered beneaththe center of the retort l5. Air enters the fan housing i9 through aninlet ring 22 mounted on the outer wall of the fan housing and providedwith adjustable dampers 23 arranged to control the rate of air flow. Theaxis of the fan wheel I! is horizontal and perpendicular to the axis ofthe ram casing.

The ram I 6 is reciprocated by a driving mechanism comprising ahorizontal rotatable shaft 25 mounted in axial alignment with the fanwheel l6 and having an eccentric 26 thereon which is operatively joinedto the ram by means of a connecting rod 21. The rear end of the rod 21is pivoted to the ram by means of a wrist pin-28 (Fig. 3). The shaft 25is supported in two bearings 33 and 3i located close to the eccentric 26and on opposite sides thereof. The bearing 80 is formed in theadjacentinner wall of the, fan housing i9, and the bearing 3| is formedin the adjacent inner wall of a box or casing 82 which serves to enclosea speed-reducing mechanism to be described hereinafter. This box 32 isprovided with a cover plate 33 which can be removed to allow access tothe interior. In the preferred construction the box 32 and the fanhousing I! are formed by a single casting which rests upon a suitablefoundation and serves to support the front end of the ram casing i2,thereby providing a very strong and rigid structure.

The eccentric 26 preferably has a diameter somewhat greater than thestroke of'the ram, and the shaft 25 is made hollow to form a quill. Thismakes it possible to extend a rotatable shaft 35 through the center ofthe quill and utilize this shaft to drive the fan wheel l8. As shownparticularly in Fig. 4, the fan wheel is mounted on one end of the shaft35. The shaft 35 is supported near the fan wheel by means of a rollerbearing 36 mounted in the quill 25, and the shaft is supported near itsother end in roller bearings 31 and 38 mounted in a sleeve 46, which inturn is rotatably supported in a bearing 4| formed in the outer wall ofthe box 32.

In order to drive the stoker I have shown an electric motor 42 mountedon the ram casing l2 directly in front of the hopper Hi, the shaft 43 ofthe motor being parallel to the fan shaft 35. The motor shaft 43 carriesa sprocket wheel ll (Fig. 4) which is connected by means of a chain 45to a sprocket wheel 46 mounted on the end of the fan shaft 35. Thewheels 44 and 46 are shown equal in diameter, so that the fan wheel IIwill be driven at the same speed as the motor shaft 43. This speed maybe relatively high, for example 1800 revolutions per minute. The motorsprocket wheel 64 is made double and is connected by means of a secondchain 68 to a sprocket wheel I! on the outer end of the sleeve 46. Thesetwo chain drives are enclosed in a suitable casing 56. The sprocketwheel 48 is considerably larger in diameter than the wheel 44, so thatthe sleeve 48 will rotate at a much slower speed than the motor shaft.However, the speed of the sleeve 66 is higher than is desirable for theram driving quill 25, and I therefore use a suitable speed reducingmechanism to connect these parts. For this purpose I provide a pinion onthe inner end of the sleeve 46, and I utilize this pinion to drive agear 52 in mesh therewith. A pinion 53 is fixed to the gear 52 in acoaxial relationship, these parts forming a compound gear which isrotatably supported on a oountershaft 54 mounted in the box 32 beneathand parallel with the shaft 35. The pinion 52 meshes with a gear 55mounted on the quill 25.

It is ordinarily desirable to operate the ram intermittently rather thancontinuously, and I therefore mount the gear 55 on a roller bearing 56(Fig. 4) on the quill 25, and I provide an automatically actuated clutchmechanism to connect the gear to the quill at predetermined intervals.As shown particularly in Fig. 4, the quill 25 is extended axially towardthe sleeve 60, and an annular hub 58 is keyed firmly to the extendedportion of the quill. Anannular clutch member- 56 is keyed to the hub 58and arranged to slide thereon in an axial direction. The member 55 andthe gear 55 are provided with cooperating clutch teeth 66 and 6|respectively which engage when the clutch membbr is moved toward thegear, and thus form a driving means for the quill 25. Coiled compressionsprings 62 are provided between the hub 58 and the clutch member 58 tourge the latter toward its driving position.

In order to control the movements of the clutch member 59, I provide themechanism shown particularly in Figs. 5 to 9 inclusive. The member 59 isprovided on its periphery with a cam in the form of an outwardlyextending rib 66 having the leading portion 65 of its operative surfaceinclined rearwardly and laterally toward the gear 55. The clutch membermay be held in its released position, against the pressure of thesprings 62, by means of a pin 66 which extends radially of the clutchmember at the front thereof and engages the side of the cam 6|. The pin66 is axially slidable in a bearing 61 formed on a bracket 68 mounted inthe box 32. A U-shaped yoke is secured to the front of the pin 66, and apin H extends forwardly from the yoke 10 in axial alignment with the pin66. The pin II is slidably supported in a. bearing 12 formed on thebracket 68, and a coiled compression spring 13 surrounds the pin llbetween the bearing I2 and the yoke 16, this spring being arranged tourge the pin 66 rearwardly toward the clutch member 59. A knob 14 ismounted on the front end of the pin ll outside of the casing, so thatthe parts can be held manually against the pressure of the spring 13 ifdesired. A pin extends rearwardly from the yoke 10 into slidableengagement with the bearing 61 to prevent turning of the yoke.

In order to withdraw the pin 66 automatically at predeterminedintervals, I form a tooth I6 on the yoke 'lll,'and I provide a rotatablecam 11 which will engage this tooth at each revolution and move the pin66 out of contact with the cam 64. This rotatable cam 11 is advanced bymeans of a ratchet mechanism comprising a hollow cylindrical casing 18to which the cam 11 is secured. Inside the casing 16 is a rotor 19 (Fig.8) having peripheral notches 86 which gradually decrease in depth towardone end, a roller 8i being located in each notch to engage the innerperipheral surface of the casing 18. With this construction clockwisemovement of the rotor will cause the rollers 8| to bind against thecasing 18 and move the same, whereas if the movement of the rotor isreversed the rollers will release their grip and the casing will remainstationary.

The rotor 19 is keyed to a shaft 83 arranged parallel to the shaft 35and mounted in bearings 84 and 85 formed on the bracket 68. A dog 86' issecured to the shaft 83 and extends rearwardly into the path of a roller81 mounted on the side of the gear 55. The upward movement of the dog 86is limited by a lug 58 thereon which engages a lug 98. A coiled tensionspring 9| extends between the bracket 68 and the dog 86 to urge the lug89 into contact with the lug 55.

In order to permit an adjustment of the rate position of the lug 98 andthereby vary the extent of oscillation of the dog 88. For thispurpose'the lug 98 is formed on the hub of a bevel gear 93 whichisrotatably supported on the shaft 83. A

screw 94 is mounted in the gear 93 and engages a peripheral groove 95 inthe shaft 83 to prevent axial movement of the gear. The gear 93 mesheswith a second bevel gear 96 mounted on a shaft 91 which is supported ina bearing 98 formed on the bracket 68. .The shaft 91 extends forwardlythrough the front wall of the box 32 and carries on its front end anoperating handle 89. The handle 89 is recessed at its upper end toreceive a ball l8! (Fig. 7) which is pressed upwardly by a coiledcompression spring I82 into engagement with a notched segmental plateI83 mounted on the bearing 98.

The operation of the invention will now be apparent from the abovedisclosure. The motor 42 drives the chain 45 and the shaft 35, thusrotating the fan wheel i8 at a high speed and forcing air for combustionthrough the duct and the gear 52 and pinion 53 to the gear 55, whichrotates slowly on the roller bearing 56. At each rotation of thegear 55,the roller 81 will strike the dog 86 and turn the shaft 83 in aclockwise direction as viewed in Fig. 7. When the roller has moved outof contact with the dog, the spring 9| will return the dog to itsoriginal position as determined by the stop 98. By moving the handle 98to various notches in the plate I83, the stop 98 can be adjusted todifferent positions through the medium of the shaft 91 and the bevelgears 98 and 93. In this way the extent of oscillation of the shaft 83can be adjusted. As the shaft 83 oscillates, it acts through the ratchetmechanism 18 to advance the cam i1 intermittently in a clockwisedirection, and when this cam strikes the tooth 16 it will move the yoke18 and the pin 66 forward- 1y. Th pin 66 will thus move out of contactwith the cam 64 and allow the springs 82 to force the clutch member 59axially toward the gear 55,

, bringing the teeth 68 into the path of the teeth 6 I.

As a result the clutch member 59, hub 58, quill 25 and eccentric 26 willstart to rotate with the gear 55, causing the ram Hi to reciprocate andfeed a charge of fuel from the hopper l 8 into the retort I5. Before theeccentric has completed one revolution, the roller 81 will strike thedog 86 again tooth, as would occur when the handle 99 is ad justed for ahigh feeding rate and the cam I1 is consequently advanced through alarge angle at each revolution of the gear 55.) This will, allow thespring I3 to throw the yoke 18 and pin 66 rearwardly, and as theeccentric completes one revolution the beveled portion 65 of the cam 64will strike the pin 66 and force the clutch member 59 axially away fromthe gear 55, moving the teeth 68 out of contact with the teeth iii andbringing the eccentric and the ram to a stop. It will thus be seen thata charge of. fuel is delivered to the furnace at each revolution of thecam 11, and the rate of advance of this cam can be controlled byadjusting the conveniently located handle 99. If it is desired tooperate the ram continuously for a short time, for example in bankingthe fire, it is merely necessary to pull the knob 14 forwardly againstthe pressure of the spring 13, thus allowing the clutch to remainenazed.

It will be noted that the invention provides a very compactconstruction, which is moreover simple and inexpensive to manufactureand install. The fan and the ram are both driven from accessible forinspection or lubrication but also out of the way of any water or asheswhich may accumulate on the firing aisle floor. This motor requires ashaft extension at oneend only, and may be of standard construction. Itwill also be noted that by reason of the positioning of the box 32 andthe fan housing l9 on opposite sides of the eccentric 26 the spaceavailable is used to great advantage. A comparatively small floor spaceis required, and the structure approximates a symmetrical arrangementabout the centerline of the ram casing II. This makes it possible toutilize inspection doors and ash removal doors at each side of thestoker if desired without interference with any of the stoker parts.Furthermore, the ram casing is located much lower than is possible informer constructions in which the fan is placed beneath the fuel feedingmechanism. For this reason the stoker is well suited for installation inconnection with boilers which are set unusually low. No externalcountershafts are employed. The stoker is entirely self-contained andcan be built and assembled in the shop, so that all diflicult problemsof aligning bearings in the field have been eliminated. All moving partsare fully enclosed, and yet they are readily accessible for inspectionor replacement upon removal of the cover plate 33. The clutch timingmechanism can be completely assembled on the bracket 68 and subsequentlymounted in its proper place in the box 32. This considerably reduces thecost of manufacture.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a hollow rotatable shaft having an eccentricthere, on, driving means for the ram'including a connecting rodoperatively connected with the eccentric, a fan housing, a rotatable fanwheel mounted in the fan housing, and a rotatable shaft extendingthrough the hollow shaft and connected to the fan wheel.

2. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a rotatable quill in front of the ram casing andhaving an eccentric thereon, a connecting rod joining the eccentric withthe ram to drive the same, a rotatable shaft extending through thequill, a fan housing anda fan wheel mounted in the fan housing anddriven by said shaft.

3. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a quill rotatable about a substantially horizontalaxis in front of the ram casing and having an eccentric thereon, aconnecting rod joining the eccentric with the ram to drive the same, arotatable shaft extending through the quill, a fan housing, and a fanwheel mounted in the fan housing, said fan wheel being coaxial with theshaft and driven thereby.

4. An automatic stoker comprising a ram casing, a fuel feeding ramreciprocable therein, a fan housing in front of the ram casing,a'speedreducing mechanism in front of the ram casing,

the speed-reducing mechanism and fan housing being laterally adjacentand located on opposite sides of the center of the ram casing, a quillrotatable about a substantially horizontal axis in front of the ramcasing and having an eccentric thereon located between thespeed-reducing mechanism and the fan housing, a connecting rod joiningthe eccentric with the ram to drive the same, driving connectionsbetween the speed-reducing mechanism and the quill, a rotatable shaftextending through the quill, and a fan wheel mounted in the fan housingand driven by the shaft.

5. An automatic stoker comprising a ram cas-' ing, a fuel feeding ramreciprocable therein, a fan housing in front of the ram casing, a box infront of the ram casing, the fan housing and the box being laterallyadjacent and located on opposite sides of the center of the ram casing,a quill rotatable about a substantially horizontal axis in front of theram casing and supported in bearings on the adjacent walls of the boxand fan housing, the quill having an eccentric thereon located betweenthe box and the fan housing, a connecting rod joining the eccentric withthe ram to drive the same, a speed-reducing mechanism in the box,driving connections between the speedreducing mechanism and the quill, arotatable shaft extending through the quill, and a fan wheel mounted inthe fan housing and driven by the shaft.

6. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a fan housing in front of the ram casing, a box infront of the ram casing, the fan housing and the box being laterallyadjacent and located on opposite sides of the center of the ram casing,a quill rotatable about a. substantially horizontal axis in front of theram casing and supported in bearings on the adjacent walls of the boxand fan housing, the quill having an eccentric thereon located betweenthe box and the fan housing, a connecting rod joining the eccentric withthe ram to drive the same, a speed-reducing mechanism in the box,driving connections between the speedreducing mechanism and the quill, arotatable .shaft extending through the quill, a fan wheel mounted in thefan housing and connected to one end of the shaft, and an electric motorarranged to drive both the speed-reducing mechanism and the rotatableshaft.

7. An automatic stoker comprising a fuel hopper, a ram casing beneaththe fuel hopper and in communication therewith, a ram reciprocable inthe ram casing, a fan housing in front of the ram casing, a box in frontof the ram casing, the fan housing and the box being laterally adjacentand located on opposite sides of the center of the ram casing, a quillrotatable about a substantially horizontal axis in front of the ramcasing and supported in bearings on the adjacent walls of the box andfan housing, the quill having an eccentric thereon located between thebox and the fan housing, a connecting rod joining the eccentric with theram to drive the same, a speedreducing mechanism in the box, drivingconnections between the speed-reducing mechanism and the quill, arotatable shaft extending through the quill, a fan wheel mounted in thefan housing and connected to one end of the shaft, an electric motormounted above the ram casing and in front of the fuel hopper, and powertransmitting means connecting the motor with the speed-reducingmechanism and the shaft.

8. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a quill rotatable in front of the ram casing andhaving an eccentric thereon, a connecting rod joining the eccentric withthe ram to drive the same, a rotatable shaft extending through thequill, a fan housing, a fan wheel mounted in the fan housing, said fanwheel being coaxial with the shaft and driven thereby, a rotatablesleeve surrounding the shaft, speed-reducing mechanism driven by thesleeve, driving connections between the speed-reducing mechanism and thequill, an electric motor, and power transmitting means connecting themotor with the shaft and sleeve to rotate the shaft at a high speedandthe sleeve at a lower speed.

9. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a quill rotatable about a substantially horizontalaxlsin front of the ram casing and having an eccentric thereon, aconnecting rod joining the cocentric with the ram to drive the same, arotatable shaft extending through the quill, a fan housing, a fan wheelmounted within the fan housing, said fan wheel being connected to oneend of the shaft and driven thereby, a rotatable sleeve surrounding theshaft at the opposite end of the quill from the fan wheel, a pinion onthe sleeve, 9. gear on the quill, means to operatively connect the gearwith the quill, means including a compound gear connecting the pinionwith the gear to drive the same, an electric motor, and two chain andsprocket drives connecting the motor with the shaft and the sleeverespectively to rotate the shaft at a high speed and the sleeve at alower speed.

10. An automatic stoker comprising a fuel hopper, a ram casing beneaththe fuel hopper and in communicationitherewith, a ram reciprocable inthe ram casing, a fan housing in front of the ram casing, a box in frontof the ram casing, the fan housing and the box being laterally adjacentand located on opposite sides of the center of the ram casing, a quillrotatable about a substantially horizontal axis in front of the ramcasing and supported in bearings on the adjacent walls of the box andfan housing, the quill having an eccentric thereon located between thebox and fan housing, a connecting rod joining the eccentric with the ramto drive the same, a rotatable shaft extending through the quill, a fanwheel mounted in the fan housing and connected to one end of the shaft,a rotatable sleeve surrounding the shaft at the opposite end of thequill from the fan wheel, a pinion on the sleeve, 8. gear on the quill,means to operatively connect the gear with the quill, means including acompound gear located beneath the shaft and connecting the pinion withthe gear to drive the same, an electric motor mounted above the ramcasing and in front of the fuel hopper, and two chain and sprocketdrives connecting the motor with the shaft and the sleeve respectivelyto rotate the shaft at a high speed and the sleeve at a lower speed.

11. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a quill rotatable in front of the ram casing andhaving an eccentric thereon, a connecting rod joining the eccentric withthe ram to drive the same, a rotatable shaft extending through thequill, a fan housing, a fan wheel mounted in the fan housing, sa d fanwheel being coaxial with the shaft and driven thereby, a gear coaxialwith the quill, means to rotate the shaft at a high speed and the gearat a low speed, a clutch to connect the gear with the quill, and meansto actuate the clutch automatically at predetermined intervals.

12. An automatic stoker comprising a ram casing, a fuel feeding ramreciprocable therein, a. quill rotatable in front of the ram casing andhaving an eccentric thereon, a connecting rod joining the eccentric withthe ram to drive the same, a rotatable shaft extending through thequill, a fan housing, a fan wheel mounted in the fan housing, said fanwheel being coaxial with the shaft and driven thereby, a gear rotatablysupported on the quill, means to rotate the shaft at a high speed andthe gear at a low speed, an annular clutch member slidably keyed to thequill, the clutch member and gear having cooperating parts which engageat one position of the member and thus cause the member to rotate withthe gear, and means to slide the clutch member along the quill atpredetermined intervals and thus cause intermittent rotation of thequill.

13. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a quill rotatable in front of the ram casing, aneccentric on the quill, a connecting rod joining the eccentric with theram to drive the same, a rotatable shaft extending through the quill, afan housing, a fan wheel mounted in the fan housing, said fan wheelbeing coaxial with the shaft and driven thereby, a rotatable sleevesurrounding the shaft, speed-reducing mechanism connecting the sleevewith the quill to rotate the same, an electric motor, and two chain andsprocket drives connecting the motor with the shaft and the sleeverespectively to rotate the shaft at a high speed and the sleeve at alower speed.

14. An automatic stoker comprising a ram casing, a fuel-feeding ramreciprocable therein, a fan housing in front of the ram casing, a box infront of the ram casing, the fan housing and the box being laterallyadjacent and located on opposite sides of the center of the ram casing,a speedreducing mechanism in the box, a horizontal r0 tatable shaftdriven by the speed-reducing mechanism, the box and the fan housingbeing shaped to provide two spaced bearings which support the shaft, aconnecting rod, means on the shaft between the two spaced bearings todrive the connecting rod, the connecting rod being connected to the ramand to the means for driving the connecting rod, a rotatable fan wheelin the fan housing, and means to drive the speed-reducing mechanism andthe fan wheel.

15. An automatic stoker comprising a fuel feeding device, a hollowrotatable shaft, means operatively connecting the shaft with the fuelfeeding device to drive said device, a fan housing, a

rotatable fan wheel mounted in the fan housing, i

and a rotatable shaft extending through the hollow shaft and connectedto the fan wheel.

JAMES P. NORTON.

